Abstract: Ni-P functionally gradient deposits and Ni-P deposits with different P contents were deposited on steel substrates by electrodeposition method. The wear behaviour of two types of Ni-P deposits was investigated comparatively. Results indicated that the graded Ni-P deposits have better composition and structure gradients in the direction of thickness. After heat treatment, the wear resistance of Ni-P gradient deposit is 1-2 times higher than that of ungraded Ni-P deposits. Wear process of Ni-P deposits were characterized by micro-crack nucleation and propagation, brittle detachment. The formation and propagation of cracks within heat-treated Ni-P gradient deposits during the wear process were effectively inhibited due to the introduction of graded composition and structures and as a result, the wear resistance of Ni-P gradient deposits was improved greatly.